Salad oil and method of oiling tin



United States Patent SALAD OIL AND METHOD OF OILING TIN PLATE THEREWITH No Drawing. Application January 7,1955 Serial No. 480,598

11 Claims. (Cl. 106-250) This invention relates in general to a method of treating glyceride oils and, more particularly, to an improved glyceride oil composition especially adapted for the oiling of tin plate.

In the plating of strip or sheet steel with tin by the electrodeposition method, mineral or vegetable oils have been used heretofore to protect the surface of the tin plate from oxidative deterioration. When tin is deposited by the electrolytic process, the coating may be regulated to any desired thickness and very thin coatings as compared to coatings produced by the hot dip method are generally possible. Tin plate is rather durable in a dry atmosphere but rusts rapidly in the presence of moisture and this is particularly so in the case of electrodeposited tin coatings since the thinner the coating, the more readily rusting will occur. After the plating process, tin plate is frequently stored in large stacks for a few months prior to manufacture into cans or other articles. A film of oil is deposited on the surface of the metal for the purpose of preserving the finish or temporarily preventing corrosion during this period of storage, and also to avoid scratching of the surface during subsequent handling and shipping. Inasmuch as an oil film remains on the metal surface even after the sheets are formed into containers, etc., the oil should preferably be edible, odor free, resistant to oxidation or polymerization, capable of retarding oxidative deterioration of the metal, and should not interfere with subsequent 'lithographing or lacquering procedures. Cottonseed oil has been used in the tinplate industry for this purpose for a number of years. However, because it is a semi-drying oil, cottonseed oil dries rapidly on the surface of the tinplate, producing a lacquerlike film which interferes with subsequent lacquering and lithographing operations as are commonly employed in the fabrication of tin cans. Another objectionable characteristic of cottonseed oil for this purpose is that it forms a gummy layer in the oiling chambers and clogs the nozzle of the device used to atomize the oil in the oiling chamber. A further difficulty is the troublesome puddling of cottonseed oil on the surface of the plate whereby portions of the plate may be exposed to the air.

It is therefore an object of the present invention to provide a novel oiling composition of superior oxidative stability.

Another object of the invention is to provide an oiling composition possessing improved wetting properties.

Additional objects, if not specifically pointed out herein, will be apparent to one skilled in the art from the following detailed description of the invention.

Generally, the products of the present invention comprises a vegetable oil (preferably refined, deodorized, winterized and bleached) treated with a stabilizing amount of an oil-soluble antioxidant and a quantity of mixed partial glycerides suflicient to give the composition good tin plate Wetting properties. Vegetable oils found most satisfactory are those classified as salad oils and exemplified by winterized cottonseed oil. The term salad "ice oil is used herein to define those oils which remain substantially liquid at temperatures of 40-4S F. The composition provides a tin plate oil of superior oxidative stability which spreads in an even film on the surface of the metal.

In accordance with the present invention, cottonseed salad oil is particularly useful as the glyceride oil component, while the partial glyceride mixture is composed of mixed glycerides in the approximate ratio of 40% mono-, 40% diand 20% tri-glycerides, derived from cottonseed oil.

While any of the well-known glyceride antioxidants may be employed in the composition, a multicomponent mixture, such as the propylene glycol dispersion commercially available and known as Sustane #3, has proven to be particularly well adapted for use in tin plate oiling. Sustane #3 contains:

Parts by weight Propylene glyc 70 Butyl hydroxyanisole 20 n-Propyl galla 6 Citric acid 4 Although the above Sustane #3 composition is considered preferable, other stabilizers containing an alkylated hydroxyanisole as an active ingredient may also be employed either alone or in combination with synergistic amounts of acids, such as citric, tartaric, or ascorbic. Usually about 0.005% to about 0.05% of stabilizer by weight of the oil to be stabilized will be used, although up to 0.1% may be employed.

The addition of the stabilizer to the novel composition can be readily achieved since the simple admixture of the oil and stabilizer is a homogeneous product.

The following example illustrates a preferred form of the novel composition:

Example Parts by weight Cottonseed salad oil 96.95 Partial glycerides 3.0 Antioxidant 0.05

The vegetable oil may be any of the well known semidrying oils, such as soybean, corn, or cottonseed oil, although winterized cottonseed oil has been found to be particularly well adapted for use in the composition since it is less likely to polymerize and form troublesome gums which clog the oiling equipment. Ideally the oil should first be refined, winterized, deodorized, and bleached.

The partial glyceride component comprises a mixture of partial esters of polyhydric alcohols produced by any of the well-known methods of manufacture of commercial monoglycerides. Although any one of a variety of monoglyceride mixtures may be employed in the practice of the present invention, a composition containing mono-, di-, and triglycerides in the approximate ratio of 40-40- 20 and derived from cottonseed oil has been found most suitable. The addition of the partial glyceride mixture in an amount, usually about 1% to 4% by weight of the oil and preferably about 3%, is easily accomplished since the mixture is miscible with the oil used. In any case, the amount of the partial glyceride mixture to be added is easily determinable by one skilled in the art as that point where the final oiling composition easily wets the surface of the tin plate and forms an even film on the surface thereof without puddling.

Obviously many modifications and variations of the invention hereinbefore set forth may be made without departing from the spirit and scope thereof and there fore only such limitations should be imposed as are indicated in the appended claims.

' salad oil.

We claim:

1. A composition for oiling electrolytically-produced tin plate which comprises: an admixture of an antioxidant; partial glycerides derived from cottonseed oil: and

2. A composition for oiling elctrolyticallyeproduced tin plate which comprises from about 0.005 %-0. 1% of antioxidant; from about 1.0%-4.0% partial glycerides derived from cottonseed oil; and from about 96%9-9-% Qfat antioxidanflfrom about 1.0-4.0 percent partial glycof an edible glyceride o'il. I

3. A composition for oiling electrolytically-produced 'tin plate which comprises an antioxidant; partial glycerides derived from cottonseed oil; and an edible semi- V drying oil.

4. A composition for oiling e1ectrolytically-produced tin plate which comprises: about 0.05% antioxidant; about 3% partial glycerides derived from cotton seed oil; and the remainder an edible glyceride oil. i v

5. A'composition for oiling electrolytically produce tin plate which comprises: about 0.05% antioxidant; and the remainder an edible glyceride oil containing about 3% of a mixture of monoand di-glycerides derived from cottonseed oil, and'cottonseed oil, said mixture being in the ratio'of 40-40-20.

6. The composition of claim 5 wherein the antioxidant comprises a mixture of a-glycol,- a lower alkyl-gallic acid ester, a lower alkyl hydroxyanisole and citric acid.

7. The composition of claim 5 wherein-theedible glyceride oil is a semi-drying oil.

8. The composition of claim 5 wherein the edible glyceride oil is cotton seed oil.

9. A composition for oiling electrolytically-produced erides derived from cottonseed oil, and the remainder an edible semi-drying glyceride oil.

11. A method of protecting the finish of tin plate material against scratching and oxidative deterioration, which comprises: depositing on the surface of said tin plate a tin plate oiling composition, said oiling composition being an admixture of at least about 0.005 percent ofa fat antioxidant, at least about 1.0 percent partial glycerides derived from cottonseed oil, and the remainder an edible semi-drying glyceride oil.

ReferencesCited in the file of this patent UNITED STATES PATENTS 1,948,582 Hunt Feb. 27, 1934 2,225,918 Martin Dec. 24, 1940 2,304,288 Swain Dec. 8, 1942 2,573,940 Von Fuchs Nov. 6, 1951 2,673,838 Veatch et al. Mar. 30, 1954 2,680,090 Rose et a1. June 1, 1954 2,759,829 Mattil et a1 Aug. 21, 1956 

1. A COMPOSITION FOR OILING ELECTROLYTICALLY-PRODUCED TIN PLATE WHICH COMPRISES: AN ADMIXTURE OF AN ANTIOXIDANT; PARTIAL GLYCERIDES DERIVED FROM COTTONSEED OIL; AND SALAD OIL. 